Pretty sure it shows a chemical reaction
The relation between density, mass and volume is

1) to calculate = volume
given:
Density = 0.0915 g/ mL
mass = 17.7 grams
formula used:

Thus
Volume 
Answer: 193.44 mL
2) the mass of sample will be

Answer: 7 g
Alka-seltzer is an effervescent antacid which neutralizes the acid of the stomach by generating CO2. The chemical formula of alka-seltzer is C16H17NaO14. In this case, if we are given the mass of the antacid used, then by stoichiometry, mass alka-seltzer * (1/ molar mass of alk-selz) * (1 mol Co2 / 1 mol alk-seltz) * (44 g/molCo2). That is how you get the mass of Co2 produced.
Answer:
A_____PENCIL______ consists of a mixture of graphite powder (a form of carbon) and clay that is baked and hardened and encased in wood or paper. a. silverpoint b. pencil c. charcoal d. chalk e. paste
Explanation:
A pencil is a writing material, where the graphite is what gives the black color to the writing stroke.